In this article I will explain cause and resolution of “System.Data.OracleClient requires Oracle client software version 8.1.7 or greater.” error
This error generally occurs when you deploy an application on the server that access Oracle database using “System.Data.OracleClient” library and it doesn’t find the library on the server.
To resolve this error you need to install Oracle Data Access Components (ODAC) with Xcopy deployment on the server which enables Oracle Data Provider for .NET (ODP.NET). Please follow these steps to install ODAC on the server
Step 1: Download ODAC component
You have to sign up to download these from oracle.com. I will download and install ODAC for 64-bit.
Step 2: Extract downloaded zip file anywhere on the system for example on the Desktop
Step 3: Open Command Prompt (cmd) and run following command to change directory to the extracted folder:
Step 4: Run following command in the Command Prompt to install Oracle Data Access Components
install.bat odp.net20 c:oracle11.2odac odac11
Step 5: Add following paths of the installed ODAC components in the Path environment variable of the system
Follow these steps to add paths to the environment variable
Step 5.1: Right click on “Computer” and select “Properties” to open the System properties
Step 5.2: Click on “Advanced system settings” to open “System Properties”
Step 5.3: Click on “Environment Variables” button under “Advanced” tab to open “Environment Variables” window
Step 5.4: Double click on the “Path” variable in the “System Variables” (scroll down if it’s not visible) section to edit the “Path” variable
Step 5.5: Add C:oracle11.2odac;C:oracle11.2odacbin; at the beginning in the “Variable value” TextBox
Step 5.6: Close all the windows by clicking on “OK” button
Step 6: Restart your system.
Note: If 64-bit ODAC component(ODAC112021Xcopy_x64) does not works in a 64-bit system, try to install 32-bit ODAC component (ODAC1120320Xcopy_32bit). It worked for me.